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<div><span class="kw">theorem </span><a NAME="T47"><span class="comment"><font color="firebrick">:: NAT_1:47</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">X</font> being   non  <a href="xboole_0.html#V1" title="XBOOLE_0:attr.1">empty</a>   <a href="hidden.html#M2" title="HIDDEN:mode.2">set</a> <br/>  for <font color="Olive" title="b2">s</font> being   <a href="nat_1.html#NM1" title="NAT_1:NM.1">sequence</a> of <font color="Olive" title="b1">X</font> holds  <font color="Olive" title="b2">s</font> <a href="nat_1.html#K7" title="NAT_1:func.7">^\</a> <a href="numbers.html#K5" title="NUMBERS:func.5">0</a> <a href="funct_2.html#R2" title="FUNCT_2:pred.2">=</a> <font color="Olive" title="b2">s</font></div></div>
